Rotary drying apparatus



May 23, 1933. A JONES 1,910,607

ROTARY DRYING APPARATUS Filed oct. 15, 1930 4 Sheets-sheet 1 ulm-Ilmmun- C \J 5/ JJ a :I d

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Patented May 23, 1933 narran STATES PATENT OFFICEA FREE A. JONES, 0F CANTON, OHIO, ASSIGNOR TO JONES AND HARTMAN, ING., OF CANTON, OHIO, A CORPORATION OF OI-IIO ROTARY DRYING APPARATUS Application filed October 15,. 1930. SeriaI No. 488,853.

The invention relates to rotary drying apparatus, and more particularly to means for drying slurry and the like, which is a fine 4 material and liquid of a semiplastic to fluid r" state, adapted 'for use in connection with a rotary cement kiln.

ln the manufacture of cement, under present practice, probably more than seventydive per cent of made by the wet process, in which about thirty-two per cent of moisture is added to the raw mix, producing an intimate mixture of material ingredients in the slurry u which is then passed through a rotary kiln i@ and burned inte a cement clinker. The water present is detrimental in burning as it must be completely driven off before burning or fusing of the material can take place.

rThis necessitates the use of considerable fuel, adding greatly to the cost of manufacture of the cement, and as a great length of time is required to evaporate the moisture from the slurry passing through the kiln, it is frequently found necessary to build the kilns of great length, two hundred and lifty to three hundred and fifty foot kilns being common for such purpose.

ln an attempt to reduce the moisture in the slurry, before the same is placed in the kiln, an apparatus known as a filter wheel or mechanical filter has been used to some extent to remove moisture from the slurry, but such apparatus is very costly to install and operate, and removes only a comparatively small portion of the moisture from the slurry, usually allowing` more than twenty of the original thirty-two parts of moisture to remain in the slurry which is placed in the kiln.

The object of the present improvement is to provide a simple and inexpensive apparatus which may be easily operated, at small cost, to remove the greater part of the moi, ture from the slurry before the same is placed in the kiln.

Another object is to provide a dryer associated with the rotary kiln through which the slrnry is afterward passed, the dryer being operated by the waste heat from the'kiln, thereby requiringl no additional fuel to operate the dryer, which greatly reduces the the cement produced today is amount of fuel required to burn the cement clinker and adds to the capacity of the kiln.

A further object is to provide means for placing the slurry, in a thin coat,` directly upon the exterior of a hot zone of the ro- W description of the invention, may be attained by constructing the apparatus in the manner illustrated in the accompanying drawings, in which Y Figure 1 is a longitudinal section of the discharge end portion of a rotary kiln, showing the improved slurry drying apparatus associated therewith;

F ig. 2, a transverse sectional view taken substantially on the line 2-e2, Fig. l;

Fig. 3, a view similar to Fig. 2, showing means for spraying the slurry upon the extorior of the kiln;

Fig. fi, a transverse section of an apparatus similar to that shown in Fig. 3, showing means for removing surplus slurry from the kiln ;y

Fig. 5, a similar View showing means for applying partially dried slurry, suoli as received from a filter wheel;

Fig. 6, a transverse section showing another modilication of the invention;

Fig. 7, a similar view showing a chain belt for applying the slurry to the kiln;

Fig. 8, a fragmentary side elevation of a portion of a rotary kiln provided with a modified form of dryer including looped chains connected to the exterior of the rotary kiln shell;

Fig. 9, a transverse sectional View through the same;

Fig. l0, an enlarged fragmentary section of a portion of the kiln shell showing the manner in which the periphery thereof is illed out by curved plates; and

Fig, l1, a detail sectional view of a inedilied form ot perforated plate.

Similar nun'ierais re'ler to similar parts throughout the drawings.

The invention may be applied to any usual and well known construction o1 rotary kiln, and ior the purpose oit the application the kiln includes the inclined rotary cylinder 10, which may have the usual refractory lining,y 1l.

@niv the d ischargge end portion of the kiln is illustrated, it being;` understood that the reu'iainder ot the kiln may be constructed, supported and' operated in any usual and Well known manner. rlhe rotary cylinder is arranged to discharge into the tiring hood 12, through which `is projected a Jfuel injectingY pipe 13, directed toward the inlet end of the cylinder 'tor iliroducing the desired temperature therein.

Located below the iii-ing loor 14, and coinmunicatingg with the tiring' hood, is a cooler in the :torni ot an inclined, rotary cylinder 15, forming,l a part oit the invention, and adapted to receive the hot cement clinker as it is discharged from the kiln and passes downward through the tiring hood.

As Will he seen from an inspection of Fig. 1the hood l2 encloses the discharge end the kiln and the inlet or charging end of the cooler, thus conveying the heated atmosphere from the cooling; cement clinker in the cooler direct y into the kiln, assisting` in heating the same.

Referring lirst to they torni of dryer shown in Figs. l and 2, the slurry is conveyed, from any suitable source of supply, through a pipe 16, to the slurrv pan 17, located beneath a hot portion ot the rotary kiln 10. It should lee understood that While the dry-er appara-- tus illustrated and described as applied to the kiln, it mav also be applied, in the same manner, to the rotary cooler 15, with equal eliect, and in the appended claims where reterence is made to the dryer applied to a rotary kiln, it is to be construed as covering also the dryer as applied to the rotary cooler.

A rotary slurry slinger is located Within the pan 17, and may comprise one or more shafts 18 provided with a plurality ot paddles 19 for slingrinn; slurry .trein the pan onto the exterior of the rotary kiln, torn'ling a thin coating thereon asV indicated at 20 in Fin'. 2. Each sha'tt 18 may be provided, at one end, With a sprocket or pulley, as indicated at 21, for applying power to drive the shaft in a direction oi/)posite to the direction of rotation of the kiln, as shown by the arrows in Fig. 2, but rotation may be in either direction though preferably as shown.

A vapor hood 22 is preferably located above the kiln, at the point Where the dryer is applied, to carry away the steam and vapors from. the drying` slurry coating` upon the rotary turn ce. r:the hood is connected to the stack Q3 which may be provided. With a condensation trap 2li.

its the rotary kiln nears the completion oi" each revolution, the greater part o1" the moisture having` been evaporated Atroni the slurry, means are provided Ytor scraping or removing; the substantially dried slurry from the periphery ot the kiln.

T his may be accomplished by means oi a scraping` bar 25, pivoted intermediate its ends, as at 26, to any stationary portion of the amniratus, such as the receiving hopper 27. Adjustable guide rolls Q8 may be carried by the scraping bar for controlling the depth oi. the cut,I and a tension spring` 29 may be provided `tor maintaining the scraping bar in operative position.

As the dried slurry scraped from the exterior of the kiln, by the scraping` bar, it passes down through the reeeivinglr` hopper and is deposited upon the receiving' conveyor, by means of Wh ich it is carried to the chargingend of the kiln, or it desired, the substantially dried slurry may lirst be passed through a rotary dryer of the type shown in my prior Patent No. 1,694,708 ot' December 11, i928, after Which it may be charged into the kiln.

Various modifications oi the means for applying the slurry coatingto the exterior of the rotary kiln, as Well as for removing' the dried slurry therefrom, may be provided, as illustrated in 3 to 7 inclusive of the drawings.

For instance, shown in Fins. 3 and t, the slurry may he sprayed upon the upper surface ot the kiln, as by the slurry feed pipes 3l. ln each. ot these cases a shield 32 may be provided for preventing` the moist slurry 'from running down the Wrong side ot the kiln, this shield beine4 pivoted as at 33, to any suitable stationary portion of the appara-tus.

rl`he scraping' device may comprise a har Slt, pivoted as at 35, to any stationary portion ot the machine and having;` a `guide roller 36 for rolling` contact with the periphery ot' the kiln, any suitable means, (not shown) beingr provided. for holding the bar in operative position.

An adjustable scraping' knife 37 is slidably mounted upon the bar and arranged to be adjusted toward or from the kiln by means of an adjusting screw 38.

.lf it is desired to provide a uniform coatink;Y of slurry upon the kiln, a coating' ,flanged to desired thickness by an adjustable roll 3l) carrying a knife edge may be used, as shown in 4f. This roll is carried upon an arm 40, pivoted, as at 41-1, to a stationary part ot the apparatus, and provided with the anoular, Weighted arm 49, for holding' the roll against the kiln. Y

The surplus slurry, removed by the roll 39,

passes down the chute 43, to a trough 44 from which it may be returned to the original slurry supply system. As the dried slurry is scraped from the kiln, by the knife, it falls into the receiving hopper 45 from which it may be carried to the charging end of the kiln by a conveyor such as the screw conveyor 46 or belt conveyor 30 shown in Figs. 1 and 2 or other well known conveying me ans, located through the lower portion of the receiving` hopper.

1n Fig. 5 is shown a modilicatiou of the apparatus designed for handling` partially dried slurry which has been passed through a filter wheel, the seniiplastic material being carried from the filter wheely by means of a conveyer 47 to the depending spout 48 from which it is deposited upon the rotating shell of the kiln, a shield 49, similar to the shields shown in 3 and` 4, being locatedadj acent to the spout for preventing the slurry from passing` downward on the wrong side of the kiln.

A packing roll 50 is provided for packing the semiplastic material in a thin coating` upon. the exterior of the kiln, this roll being carried upon an arm 51 pivoted as at 52 to a stationary portion of the apparatus, a weighted arm 53 beineconnected thereto for urging the packing roll toward the kiln.

The dried slurry is removed from the kiln by means of a revolving brush or scraper 54 carried upon an arm 55 pivot-ed at its upper end to any suitable stationary portion of the apparatus and having an angular weighted arm 55 connected thereto for holding the revolving brush against the kiln.

A pulley or sprocket 57 .may be xed upon the brush shaft and connected as by a belt or chain 58 to the sprocket or pulley 59 which is driven by a belt or chain 60 from any suitable source of power in order to vcontinuously rotate the brush during the operation of the apparatus.

The dried slurry removed by the revolving brush drops into the receiving hopper G1 and is carried to the charging end of the kiln as by the conveyor 62.

In the form of the invention illustrated in Fig. G, curved slurry application pan G3 may be pivoted to a stationary portion of the apparatus at a point adjacent the under side of the rotary kiln, as indicated at 64, and provided with a weighted arm (35 for holdin g the pan. in substantial contact with the periphery of the kiln, an adjustable guide roll G6 being` carried upon an arm 67 pivoted to a lug 68 upon the pan and provided with an adjusting screw 69. Slurry is fed to the pan 63 as b v the feed pipe 70 and contacts with the periphery of the rotating.;` kiln, forming a coating thereon as shown.

For the purpose of removing the dried slurry coating from the kiln, a revolving brush 71, similar to the brush 54, may be provided, the dried slurry being removed by the brush and dropped into the receiving'ho'pper 72 from which it is carried to the charging end of the kiln as by the conveyer 73.

Another modification is shown in Fig. 7, in which a slurry pan 75 is located beneath the rotary kiln, slurry being rfed thereto in any suitable manner. A continuous link web or belt 76 is located around the kiln., being guided over the rollers `77 and beneath the roller 78,located in the slurry pan.

As the kiln rotates, a coating of slurry is continuously picked Vup upon the link web or belt and carried around the kiln, the `dried slurry being removed from the kiln as by the hammer 79 which may be mounted upon the arm 80 pivoted as at 81 to a stationary portion of the ai'iparatus and oscillated in any suitalile manner as by the pitman 82 and wheel 83. rlfhe dried slurry drops into the receivin hopper 84 and is carried to the charging end of the kiln as by the conveyer 85;kk i

It vshould be understood that in the form of the invention shown in 2 to 6 inclusive, where a scraper is employed to remove the dried material, a revolving brush may be substituted therefor and vice versa.

1n the form of the invention shown in Figs. 8 and 9, the dryer may comprise a plurality of short lengths of chain 87 connected at both ends to the kiln shell at points spaced apart so as to .han in curved loops which will hang down from the lower portion of the kiln and lie against the shell at the upper portion thereof as best shown in Fig. 9.

slurry pan 88 is provided beneath this portion of the kiln shell, the chain loops dragging through the slurry as the shell is rotated, cach loop picking up a portion of slurry which it carries around the shell for the purpose of dryin the same.

Slurry may be supplied to the pan 88 by means of the slurry supply pipe 89 and an crei-flowpipe 90 may if desired be provided in the pan for u'iaintaining the desired level of slurry therein.

A bar 91 may be fixed. above the kiln, at one side of the center thereof and substantially parallel to the axis of the kiln shell, a flexible chain retarder shown at 92 being carried by the bar and adapted to drag over the surface of the kiln and the chain loops as they approach the beating hammer 93 which may be operated by any suitable mechanism strike the descending chain loops 87 and break the dried slurry therefrom.

This operating means is shown in Fig. 9 in whiclrthe hammer 93 is carried upon one end of a lever 94 pivot-ed to a stationary portion of the apparatus as at 95 and arranged to be normally urged away from the kiln as by the spring` 96. f

l .he connecting rod 97 is pivotally attached to the lever 94, intermediate the ends thereof, as `shown at 98 and is operated by the rcvolving cam 99 to cause the hammer to strike rapid blows against the chain loops.

The dried slurry broken from the chain loops drops into the receiving hopper 100 from which Ait may be carried away by the screw conveyor 101 or a belt or other suitable Y form of conveyer which carries the dried slurry to the charging end of the kiln.

It should be understood that the kiln shell is shown conventionally in Figs. l to 9 inclusive as owing to the small scale upon which the figures are drawn .the structural details of the shell cannot be properly illustrated. However, it should be remembered that kiln shells are ordinarily provided with butt straps as shown at 102 in Figs. 10 and il, these straps extending' longitudinally of the kiln at spaced points.

ln order to carry out the present invention on kilns as ordinarily made, it is desirable to fill in the spaces between these butt straps so as te provide a continuous cylindric outer surface for receiving the slurry. This is preferably done by placing,l curved plates 103 upon the exterior of the shell l0, filling the spaces between the butt straps and providing a continuous cylindric outer surface as shown 'in Figs 10 and 11.

In order to assist the slurry in adhering to the surface of the kiln by producing a suction, these curved plates may be provided with sockets n104C drilled or otherwise formed therein as shown in Fig. 10 or with apertures 105 punched or otherwise formed entirely through the curved plates as shown in Fig'. 11.

wWith these openings in the outer surface of the kiln it will be seen that as the slurry is applied to the kiln it will be received in the openings, not only causing this portion of the slurry to dry rapidly but also causing additional slurry to adhere to the slurry contained in the openings.

Then the wet slurry is first applied to the surface of the kiln, little, if any, of it will adhere to the outer surface of the kiln although the sockets or apertures will be quickly filled with slurry which rapidly dries from the heart of the kiln. As additional wet slurry applied to the surface of the kiln, it will adhere to the multiplicity of small surfaces of dried slurry located in the sockets, this adherence being caused by the dry slurry in the sockets absorbing' the moisture from the new coat of wet slurry which is quickly dried outI by the heat of the kiln and as the coating' of dried slurry is scraped from the surface of the kiln, the slurry remaining in the sockets is rapidly dried and in condition to receive and hold another coating of wet slurry.

On new kilns of the welded type, made for using this dryer, the conventional butt straps can be dispensed with and the drying surface with its sockets can be'made on the kiln shell or a curved plate can be attached to the exterior of the kiln shell t-o form a continuous surface.

I claim:

l. ln combination with a rotary kiln having` sockets in exterior surface, means for applying' a thin coating of slurry upon the exterior surface of the kiln, and means for removing' the slurry from the surface of the kiln after it has been dried by the heat of the kiln.

2. ln combination with a rotary kiln havin g sockets in its exterior surface, means for applying a thin coating of slurry upon the exterior surface of the kiln, means for removingl the slurry from the surface of the kiln after it has been dried by the heat of the kiln, and a receiving hopper for receiving the dried slurry as it is removed from the surface of the kiln. Y

3. ln combination with a rotary kiln havin sockets in its exterior surface, means for applying a thin coating' of slurry upon the exterior surface of the kiln, means for removingthe slurry from the surface of the kiln after it has been dried by the heat of Vthe kiln, and means for conveying' the dried slurry to the charging end of the kiln as it is removed from the surface of the kiln.

in combination with a rotary kiln having' sockets in its exterior surface, means for applying a thin coating of slurry upon the exterior surface of the kiln, means for removing the slurry from Ithe surface of the kiln after it has been dried by the heat of the kiln, a receiving; hopper for receiving' the dried slurry as it is removed from the surface of the kiln, and 1n cans for conveying the dried slurry from the hopper to the charging end of the kiln.

5. ln combination with a rotary kiln having sockets in its exterior surface, a slurry pan adjacent to the kiln, means for applying' a thin coating of slurry from said pan upon the exterior surface of the kiln, and means for removing the slurry from the surface of the kiln after it has been dried by the heat of the kiln.

6. in combination with a rotary kiln having sockets in its exterior surface, a slurry pan adjacent to the kiln, means for applying, a thin coating` of slurry from said pan upon the exterior surface of the kiln, means for removing' the slurry from the surface of the kiln after it has been dried by the heat of the kiln, and a receiving hopper for recei ving the dried slurry as it is removed from the surface of the kiln.

7. In. combination with a rotary kiln having sockets in its exterior surface, a slurry pan adjacent to the kiln, means for applying a thin coating of slurry from said pan upon the exterior surface of the kiln, means for removing the slurry from the surface of the ill5 kiln after it has been dried by the heat of the kiln, and means for conveying the dried slurry to the charging end of the kiln as it is removed from the surface of the kiln.

8. In combination with a rotary kiln having` sockets in its exterior surface, a slurry pan adjacent to the kiln, means for applying a thin coating of slurry from said pan upon the exterior surface of the kiln, means for removing the slurry from the surface of the kiln after it has been dried by the heat of the kiln, a receiving hopper for receiving the dried slurry as it is removed from the surface of the kiln, and means for conveying the dried slurry from the hopper to the charging end of the kiln.

9. In combination With a rotary kiln having sockets in its exterior surface, means for applying` a thin coating of slurry upon the exterior surface of the kiln, and a scraper bar for removing the slurry from the surface of the kiln after it has been dried by the heat of the kiln.

l0. In combination -With a rotary kiln having sockets in its exterior surface, means for spraying a thin coating' of slurry upon the exterior surface of the kiln, and means for removing the slurry from the surface of the kiln after it has been dried by 'the heat of the kiln.

l1. In combination With a rotar-y kiln having curved plates attached to the exterior of the kiln, means for applying a thin coating` of slurry upon the exterior' surface of the plates, and means for removing the slurry after it has been dried by the heat of the kiln, the curved plates having sockets in their exterior surfaces to cause the slurry to adhere thereon.

In testimony that I claim the above, I have hereunto subscribed my name.

FRED A. JONES. 

